1. Field of the Invention
The present invention relates to a bag supply apparatus for supplying bags to a conveyer for transporting a bag bundle stacked in such a format that the upper level bag is shifted in a forward direction and more specifically to a bag supply apparatus that supplies bags to a belt conveyor of a conveyer magazine type bag supply apparatus.
2. Description of the Related Art
A bag supply apparatus of the type described above is disclosed in, for instance, Japanese Patent Application Laid-Open (Kokai) Nos. 8-337217 and 2004-210473.
In Japanese Patent Application Laid-Open (Kokai) No. 8-337217, a bag bundle (a group of bags stacked in a manner that the upper level bag is shifted in a forward direction with respect to the conveying direction of the belt conveyor of the bag supply apparatus) transported on the belt conveyor of a conveyer magazine type bag supply apparatus is transported forward; and when the bag bundle has passed a prescribed point, a push-up rods disposed below the belt conveyor is moved upward and lifts up the rear edge of the bag bundle (FIGS. 1 through 6 in this laid-open publication), or a drop-down rods disposed above the belt conveyor is lowered, engaged with both edges of the proximity of the rear edge of the bag bundle, and then raised to lift up the rear edge of the bag bundle (FIGS. 7 and 8). A replenishing bundle of stacked bags is fed from the rear into the empty space formed between the lifted-up bag bundle and the conveyance surface of the conveyer.
In Japanese Patent Application Laid-Open (Kokai) No. 2004-210473, a bag bundle (a group of bags stacked in a such format that an upper level bag is shifted in a forward direction) transported on a belt conveyor of a conveyer magazine type bag supply apparatus is transported forward; and when the bag bundle has passed a prescribed point, a push-up rods disposed below the belt conveyor is moved upward and then a support arms disposed above the belt conveyor rotates to lift up the rear edge of the bag bundle from the rear (FIGS. 1 and 2 in this laid-open publication), or a support arms disposed above the belt conveyor is lowered and rotates at the lower edge to pull the rear edge of the bag bundle from the rear and then is moved upward to lift up the rear edge of the bag bundle (FIGS. 5 and 6). A replenishing bundle of stacked bags is fed from the rear into the empty space between the lifted-up bag bundle and the conveyance surface of the conveyer.
The apparatuses disclosed in Japanese Patent Application Laid-Open (Kokai) No. 8-337217 have problems. In the bag supply apparatus that uses the push-up rods, the push-up rods interferes with the pushing-in motion of the replenishing bag bundle; while in the bag supply apparatus that uses the pull-up rods, a complicated operation is involved for the pull-up rods that make a drive mechanism thereof more complicated as well. In addition, in the bag supply apparatus of Japanese Patent Application Laid-Open (Kokai) No. 2004-210473, a 3-step operation is required to raise the rear edge of the bag bundle; and in the system that uses the push-up rods and the support arms makes the apparatus more complicated, while in the system that uses just the support arms, the actuation mechanism is more complicated. Furthermore, the apparatuses in the above-described two related arts both involve reciprocating actions; and thus, these apparatuses are not suited for high-speed operation and unavoidably generate vibrations and noise when stopped.
Furthermore, in the apparatuses of the above-described two related arts, since a stacked bag bundle (a group of bags simply layered top to bottom) is fed onto the belt conveyor of the conveyer magazine type bag supply apparatus, the upper level bag needs to be arranged by hand on the belt conveyor so that it is shifted in a forward direction. On the other hand, there is such a strong demand for a conveyer magazine type bag supply apparatus that the bag bundle is automatically formed in such a format as described above with at a predetermined pitch (interval) on the belt conveyor; as a result, such attempts have been made that one bag is fed at a time at a predetermined pitch (time interval) for that purpose. In that instance, the pulling-up or pushing-down processing capability for the bag bundle needs to be improved further compared to a case that feeds a stacked bag bundle. However, the processing capability in the apparatuses described in the above-described two related arts, Japanese Patent Application Laid-Open (Kokai) Nos. 8-337217 and 2004-210473 is inadequate.